The Laboratory continued its series of analyses that use linear structural equation techniques to examine the relationship between memory function and different types of penetrating missile head wounds. This research is based on work the Laboratory is doing using similar analytical techniques to investigate the architecture of memory in normal individuals. This year the LSES began using structural equation modeling PET measures to determine the underlying structure of CNS networks that subserve the various functional states (motor, cognitive etc.) during which the images were obtained. Very preliminary models have been obtained from data from small samples of normal subjects. These models are now be estimated on data from subjects with Tourette's Syndrome to test hypothesized differences in brain functioning between the two groups.